Sheffield | 25-SDC-Nov | Sheida Shabankari | Sprint 1 | analyse refactor functions

[sheida-shab]

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• My changes meet the requirements of the task
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This PR refactors the following utility functions:

• calculateSumAndProduct
• hasPairWithSum
• removeDuplicates
• find_common_items

Changes include:

• Optimizing duplicate removal in removeDuplicates using Set (O(n) instead of O(n²)), preserving the order of first occurrences.
• Optimizing find_common_items using Python sets and intersection (O(n + m) instead of O(n × m)), which is optimal.
• Optimizing hasPairWithSum using the two-pointer approach after sorting (O(n log n) instead of O(n²)).
• General code cleanup in all functions for readability and maintainability.
• Added explicit documentation of time and space complexity before and after refactoring.

All refactored functions preserve the original behavior and have been tested to ensure correctness.

Time and space complexity have been improved where applicable:

• removeDuplicates: Time O(n), Space O(n), Optimal O(n)
• find_common_items: Time O(n + m), Space O(n + m), Optimal O(n + m)
• hasPairWithSum: Time O(n log n), Space O(1), Optimal O(n)
• calculateSumAndProduct: Time O(n), Space O(1), Optimal O(n)

References:

• JavaScript Set: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set
• Python set intersection: https://www.w3schools.com/python/ref_set_intersection.asp